Field of the Invention
The present invention relates to a wireless local area network (WLAN), and more particularly, to a method for providing a terminal with information of access point (AP) selection in a WLAN system, a method for selecting an AP, and a station for supporting the methods.
Discussion of the Related Art
With the advancement of information communication technologies, various wireless communication technologies have recently been developed. Among the wireless communication technologies, a wireless local area network (WLAN) is a technology whereby Internet access is possible in a wireless fashion in homes or businesses or in a region providing a specific service by using a portable terminal such as a personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP), etc.
Ever since the institute of electrical and electronics engineers (IEEE) 802, i.e., a standardization organization for WLAN technologies, was established in February 1980, many standardization works have been conducted.
In the initial WLAN technology, a frequency of 2.4 GHz was used according to the IEEE 802.11 to support a data rate of 1 to 2 Mbps by using frequency hopping, spread spectrum, infrared communication, etc. Recently, the development of a wireless communication technique applies orthogonal frequency division multiplex (OFDM) or the like to the WLAN to support a data rate of up to 54 Mbps.
In addition, the IEEE 802.11 is developing or commercializing standards of various technologies such as quality of service (QoS) improvement, access point (AP) protocol compatibility, security enhancement, radio resource measurement, wireless access in vehicular environments, fast roaming, mesh networks, inter-working with external networks, wireless network management, etc.
In the WLAN system, a terminal used as a non-AP station performs a scanning process to find an accessible AP. The scanning process is a process in which the terminal obtains information on each AP and a list of candidate APs to which the terminal is associated in a subsequent process (i.e., an association process) so that the terminal becomes a member of a specific extended service set (ESS).
If terminals having a high channel correlation are associated with the same AP, it is difficult for the AP to provide a service simultaneously to the plurality of terminals having a high channel correlation. Therefore, when a terminal selects an AP, it is advantageous to select an AP not associated with a terminal having a high channel correlation. The scanning process may be used in order for the terminal to obtain information indicating whether other terminals having a high channel correlation are associated with a certain AP. By performing such a scanning process, the terminal can further effectively select the AP.